1. Field of the Invention
The present invention relates to an image forming apparatus, a toner supplying method, and a computer program product.
2. Description of the Related Art
In an electrophotographic image forming apparatus, there is a need to keep an amount of toner in a developing unit at a constant level. This is because an excessive low amount of toner may cause a blurring or uneven density in the print image, and an excessive high amount of toner may cause a degradation of toner. Therefore, it is required for this type of image forming apparatus to accurately supply an appropriate amount of toner, which is complementary with a toner consumption in the image forming process, from a toner bottle or the like to the developing unit.
For example, Japanese Patent Application Laid-open No. H05-297720 discloses a technology for calculating an engaging time of a toner supply clutch (so-called “clutch ON time”) required to supply an appropriate amount of toner, commensurate with the toner consumption, on the basis of an estimation of the toner consumption and a signal from a sensor, and supplying the toner by driving the toner supply clutch for the calculated engaging time.
However, there is ordinary seen variations or differences among products such as the toner supplying unit that supplies the toner to the developing unit or the driving unit for the toner supplying unit. Therefore, the amount of toner supply varies among products, even if the toner is supplied to the developing unit by driving the driving unit for the same time. Thus, it is difficult to supply the required amount of toner accurately.